I am in New Zealand & have an 83 f250, 351W that I bought recently from a Californian owner.

It originally had a Duraspark 3 system, but this gave him ongoing trouble & was replaced with an identical looking distributor, but it has a new modulator & does not use a crankshaft position sensor (although the originals were both left in place - I think for smog inspections). I think from what he said (& didn't say), that it may have more manual tuning capability than the old distributor. It has no vacuum advance.

Overall the truck is excellent, but it has cut out on me 3 times in the last 2 weeks without any warning - no missing, coughing etc, just died as if the key was turned off.
In 2 cases it was sitting idling when it stalled; the third time, it was also idling but had just been driven for about 15 minutes. But I have also done a couple of 2 hour trips without any problem at all.

Each time it would crank over fast but not re-start. But then with a couple of minutes wait, it started & ran fine. I did notice it sometimes attempted to fire upon releasing the key back to the 'run' position. But when it did restart, it was as if nothing had ever been wrong.

Does anyone have any ideas what may be wrong? Also, does this sound like a TFI-4 distributor? ( no CPS & no vacuum advance). We have various electronic systems on the market over here but not Duraspark

Thanks - I'm fine on mechanical but out of my depth with electronics

 

It would help us if you had a picture to post just so we could have a better chance or
if you see any part numbers or castings of any kind that could help narrow it down.
The Tfi module is mounted on the side of the distributor and is a rectangle about and
pretty thin it has a oval connector for the wiring and quite a few contacts inside.
If you go to autozone.com and search for the part you'll see a picture, They also have
manuals, wiring diagram, vac diagrams online for free!! IF you feel up to it when it is
not starting put a screwdriverin the coil wire and hold it or place (becareful high voltage)
it where it is about 1/4" from a grounded metal and have someone crank it over and
see if you have spark. How many miles do you put on it aa month?

 

This doesn't sound right. A dist with no vacuum advance connection is just a pickup that gives a pulse to the module, and a rotor that points the spark to the correct cylinder. There is no timing weights or vacuum advance timing inside at all. If you run this type of dist with no computer hook-up, then the timing is locked in one position, and fuel mileage and performance are poor.

Instead of trying to fix what you have, I would hunt up the parts you need to make it right. In the process of doing that, you probably will fix your problem. You have several options. You can go duraspark II, with a module and a dist that DOES have a vacuum advance, you can go with a hotrod type ignition and dist like MSD, and there are aftermarket distributors that have HEI electronics in them.

 

I was thinking that maybe he has an aftermarket ignition system on there already and
a picture is worth a thousand words!! It would suck to ditch a performance dist and
ignition system to put in a stock ford one. Pictures and any numbers cast in or even
a sticker or something that is covered in grease, clean up the parts and let us know
what you find there has to be at least some kind of casting marks maybe inside under
the rotor??

 

If he has a race dist with no vacuum advance, he would get better fuel mileage by swapping that out.

 

Thanks fellas

I'll get a photo of both the distributor & it's control box (this has been mounted inside the glovebox), & see if I can get any sort of identification

Ken

 

possibly a bad ig nition switch?
u did say it tried tp start as u released the key.....

thats a sign of a bad ignition switch.

 

Here are a couple of shots of the distributor & it's control box. There's not much identification on either.

1. The distributor has, in smudged ink - MP (or maybe WP)
- REMFG
- LA R9 (or maybe LA R2)

2. The control box has printed on the resin - 'P2S'

3. Both the control box & the rotor have 'Standard' stamped on them











It died on me 3 times today, always at an idle, & each time coughed ( actually started once), as I released the key

 

Missing photos for above post

 

Yes, that looks like a factory computer controlled distributor. If your computer system has been torn out or is inoperable, then you have no timing control whatsoever.

 

I've just had an e-mail back from the previous owner's nephew. He found out from the mechanic involved that the distributor is a Duraspark 2, with the vacuum advance removed for disguise, & the advance weights locked in place.

I can't quite figure why they went this route, but at least I know what I have. The truck is giving 20 mpg (imperial gallons) on an open-road trip, as is. I don't know if I can hope for more than that with a new distributor fitted, but power should be better.

Where did vacuum for the advance originally come from on a Motorcraft 2150 carb?

 

Here is a diagram:

 

Usually it was hooked on the passenger side on one of the ports that has no vacuum at idle, but vacuum when you rev the engine. The above diagram shows some components inbetween the port and the dist connection, but you usually can eliminate that especially if the rest of the system has had lobotomy.

 

Thanks again, Dave & subford

 

In case it helps anyone now or in the future -

This problem, apart from being infuriating & embarrassing, was becoming more frequent & risky at traffic lights etc. It was also hard on the starter, as it somehow threw the timing out temporarily (I guess via the aftermarket module) & would kick back on the pinion.

After repeated hunts, we finally found a fault in the pickup wiring plug. It appeared to be fine - clean & coated in dielectric grease, & showed continuity but I had narrowed the problem to this short loom. We cut the connector out & soldered the joint - PERFECT SINCE!
Still don't know why the problem only occurred at idle.

But after living with this gremlin for this long, I'm a happy man!